A process is often controlled by a control system that includes a fast (e.g., 10 MB or faster) native network and a slow (e.g., 31 KB) non-native network. In such a system, there is a need for communication between the devices of the fast native network and the devices of the slow non-native network. For example, a part of the process may require that an intelligent valve in the slow non-native network be actuated based on a temperature monitored by a temperature sensor in the fast native network. A control processor in the fast native network controls this part of the process by gathering the temperature data, processing the data according to a control program and communicating a control signal for the valve of the slow non-native network.
Typically, data of the non-native devices is accessed by two or more clients (e.g., a host computer or the control processors) in the fast native network. These clients may have to wait for their accesses to be serviced due to the slow speed of the slow non-native network. This can result in long delays that hinder processing in the fast network and affect the control of the process.
There is a need for a simple and flexible communication system that reduces the delays caused by the speed difference between fast and slow networks that control a process.